Conventional in-the-ear (ITE), in-the-canal (ITC) and completely-in-the-canal (CIC) hearing aids generally have similar topologies and are differentiated by their respective sizes. ITE hearing aids are generally larger than ITC units which are generally larger than CIC hearing aids. These units typically include a receiver, a microphone, a replaceable battery and amplification electronics contained within a semi-rigid housing. To prevent acoustical feedback, the hearing aids can also include a compliant acoustical sealing element that includes the space between a hearing aid and an ear canal.
Developments in hearing aid technology have included the use of a flexible or compliant tip in a hearing aid. The use of a flexible tip provides an acoustic seal between the hearing aid and a user's ear canal. The flexible tip also allows the hearing aid to mold and conform to the geometry of the user's ear canal. Substantial geometric variability exists among various users' ear canals. Such geometric uniqueness requires custom fitted hearing aids to be made. The custom fit minimizes discomfort in a user when wearing the hearing aid and helps to prevent acoustic leakage from the hearing aid which can produce feedback.
Use of the flexible tip in conjunction with a hearing aid provides relatively deep fitting of the hearing aid within a user's ear canal. However, with the use of a flexible tip, the electric components of the hearing aid are located within the hearing aid base unit. Typically, a hearing aid with such a construction is formed as an ITC unit because of the size limitations caused by the geometry of the components. The overall size of the hearing aid depends upon the size and placement of these components within the hearing aid unit.
The overall size of the hearing aid depends upon the size and placement of the components within the hearing aid. The receiver generally consumes a significant fraction of the hearing aid's internal space, thereby being a factor in controlling the overall size of the hearing aid. Because the receiver is located within the body or base unit of the hearing aid, away from an eardrum of a user, the receiver requires a relatively large amount of power from the battery of the hearing aid in order to produce sound to travel through the residual air volume formed in the flexible tip and ear canal to the eardrum, with minimal loss.
A need exists for a reduced size hearing aid, such as a CIC hearing aid, that includes a flexible or compliant tip and reduced power requirements for the receiver.